You know the old approach. Long press the text box to bring up the Paste option, and then tap this option to insert your text. It's not necessarily hard but believe me when I say there's a better way.

With iOS 13, you can insert text with just one swipe. After copying the text – perhaps even with the new copy gesture – you can simply paste it by swiping it out with three fingers. It's essentially like a pinch of zooming, but with three fingers. When you do this, an "insert" bubble will appear at the top of the display, confirming that you have performed the gesture correctly. The following GIF file provides information about how to run it correctly.